Solderer
Thanks to Bluewelders and Milwiron......you were right.
It took my brother all of two minutes to locate my wiring error. I am embarassed to admit that I wired the two middle lugs on the small rectifier to the DC side of the main rectifier.....yes, I am a dummy!
Once we moved the connections to the AC side of the rectifier, the welder works like a champ. My feeling is that it has picked up some power; definitely makes a different sound when welding. The motor speed with one 100uF cap is just fine for my welding style and speed. I am awaiting the arrival of a 220V muffin fan before using the welder extensively.
Just for your info, my brother checked the voltage while I was welding and reports 35V constant when welding with a peak of about 39V. Hopefully, this will allow my 100,000 uF 35V cap to work for a long time........hopefully.
For those of you who are neophytes and electronically challenged like me, here is a photo showing the location of the AC input side of the main rectifier. Hope this helps someone.
Thanks again for your help.......I am a happy camper and quite happy with my little HF 151!
WeldingWeb Craftsman
As I remember, one of the original photos shows air vent holes to the bottom left of the transformer. If possible, block that vent and force more air through the cabinet. You want as much air to pass through-around, inside the cabinet and exit out the back.
A second set of eyes is always a help.
WeldingWeb Artisan
Glad you got it.
I didn't realize "Hot Rodding" 151 welders would be so popular.
WeldingWeb Apprentice
Perfect, I am going to order the parts for this asap. I have been waiting for a detailed writeup for awhile now. Thanks! I was having arc stability problems just the other day patching up my leaking compressor.
WeldingWeb Apprentice
Just went to place my order and the 100000UF Cap is backordered at digikey.
WeldingWeb Artisan
The only capacitor that I see in stock, that is about the right size is this one.
http://www.newark.com/united-chemi-c...6DA823F050CD2A
WeldingWeb Journeyman
jrw21 - or anyone that might be interested - i got a little too excited when looking for caps and bought a 60000uF 50 volt which turned out to be slightly too large to fit in the main compartment. it can however be fit under the wire roll in the adjacent compartment. i was going to do that but ran across two smaller caps that i paralleled instead.
i paid $9 for it and would be happy to sell it for that + actual shipping if anyone is interested.
Last edited by d94jonca; 11-15-2009 at 10:12 AM.
WeldingWeb Craftsman
What did you finally install?Originally Posted by d94jonca
WeldingWeb Journeyman
two 30000 uF / 50 v caps that i paralleled, so same specs as the bigger one but the form factor allowed them to go in in front of the fan, which i preferred.
WeldingWeb Apprentice
If any one is intersted I have a 100000uf 60vdc cap that i'll let go for $15+shipping
WeldingWeb Apprentice
Thanks guys for all the modding advice. I love taking something cheap and making it better.
I picked up a 151 recently on craigslist for $40 and I'm starting to gather supplies to do the cap/fan/other mods. The gun that came with my welder was done. I understand a new gun from HF is fairly inexpensive but I HATE (can't empahsize this enough), HATE this cheap a$$ gun. Anyone ever do a euro torch conversion? I saw this on fleabay:
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT
It comes from the UK and is a little too pricey for my blood. Anyone have ideas to adapt another torch to the 151?
WeldingWeb Artisan
You can wire about any torch to any welder.
But by the time you add an Euro torch, connector and a gas valve to the welder , you will be looking at 150-250 dollars.
WeldingWeb Apprentice
Thank you Bluewelders that was the ticket for me. I just attached a 10k pot in place of the R9 resistor and mounted it under the wire drive rollers. so that i can make minor adjustments depending on what I am working on. This slowed the motor down perfectly!!
WeldingWeb Journeyman
What size (diameter) capacitor can fit in? How much space should be between the transformer reactor and the capacitor? The transformer and reactor would be pretty hot, not a good thing for capacitor near by. Would it be better placing capacitor at the other side of the wall, where the wire spool at, to stay away from the temperature? and the capacitor can be wired to the electrical output posts that the gun and ground clamp attached to. Bad idea?
WeldingWeb Craftsman
Bad idea, putting the cap in the spool compartment runs the risk of shorting across the terminals. Better to up the air flow and keep things cool. Be sure air is flowing through the case from one end to the other, not leaking out any gaps or seams.
WeldingWeb Artisan
If you hook the capacitor across the output leads, you will end up with the capacitor and the choke hooked in the wrong order.
The capacitors I use are usually rated for at least 85 degrees centigrade, which is about 185 Fahrenheit.
If you use a good fan they should stay a lot cooler than that.
WeldingWeb Journeyman
i dont see why putting it in the spool compartment would increase the risk of shorting anything.i was originally planning on doing that but ended up sqeezing them into the main compartment, mainly for aesthetics. you'd have to drill a hole for the leads though, since they cannot connect on the terminals in the spool compartment.
Last edited by d94jonca; 11-28-2009 at 01:38 AM.
WeldingWeb Apprentice
it could short out if you get a rat nest from the welding wire. but that is where I put mine I just used electrial tape to cover the top of the cap.
WeldingWeb Journeyman
Nice article, I may have to do a similar mod to my little welder, but I found this thread while doing a search on adapting the euro torch. I just place an order from a source in China that I've purchased from in the past. If you like I'll post updates once the items come in and I do the conversion.
WeldingWeb Artisan
Sure, always good to see the options.
How much will it cost, using the import parts ?
WeldingWeb Journeyman
for the torch, it's $31.00 and the adaptor for the machine is $10.00 as for the gas valve those can be purchased locally. Now don't get too excited about the prices, because now you have to add in shipping from China + tarrifs etc. Which by the time you get done more than double the cost. Not sure what shipping on just those 2 items are, since I placed an order for other stuff as well. I figure I'll have right around $100 invested in doing the mod when I'm done.
I attached an image of which adaptor and MB15 torch he is sending me.
WeldingWeb Apprentice
Looks good Bruce. Prices should come down some if you ordered in quantity. Perhaps a group buy?
WeldingWeb Journeyman
Still waiting for my order from china, but in the meantime I went ahead and got the parts to do the cap mod. Finished installing the parts today and all seems fine, just have to wait to attach the new torch before I can compare the differences.
Mine isn't a HF unit but an Astro Power MIG 130 110v model made in Italy that I've had since 1986 with quite a bit of usage. The internals are very similar in design, so I'd rather keep my write-up in this thread.
Basically the original torch is worn out and would cost more to replace it than do the conversion. From what I've read on another forum this model was made with many different badges, Cebora, Snap-On, BOC to name a few.
Installing the cap was very easy, but decided to mount it in the spool compartment and covered the negative terminal so there won't be any issues with shorts. Added the second bridge rectifier for the wire feed unit since it ran erratic with the new cap installed. No issues, the speed control actually operates smoother now.
One of the mods I had to do was add a solenoid gas valve since the original was a mechanical one in the torch.(which I never really liked) That was a very simple addition using a 120v unit and tying the wires to the main relay. installing that in the spool compartment too, since it'll be easier to attach the new lines.
The fan mod I did about a month after I originally purchased the unit....
WeldingWeb Craftsman
Looking at the additional cap, I’d insulate both terminals. It looks like the air exits through the bottom vents under the transformer, leaving the rectifier in a dead air zone. With the additional cap, the diodes will be working harder and would benefit from added cooling. See what you can come up with to get air to flow through the heat sink plats. Does the cover have vent holes near the heat sink?
WeldingWeb Artisan
What is the wire that is sticking up from the capacitor, toward the wire feed ?
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